As software systems continue to grow and evolve, locating code for maintenance tasks becomes increasingly difficult. Studies have shown that combining static global concern location techniques like search with more structure-based local techniques can improve effectiveness. However, no studies have yet investigated why this occurs. In this paper, we investigate why combining global and local techniques improves effectiveness, and under what conditions. We explore such questions as: “What are the limits of lexical information in locating concerns?”, “How far away does a local technique have to go to locate the remaining relevant elements?”, and “How sensitive are these results to the query or scoring thresholds of the techniques?”. The results of our study can inform design decisions to maximize effective global and local combinations in future concern location techniques.